THE SHORTEST DAY.

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Dave Brown
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Re: THE SHORTEST DAY.

Post by Dave Brown » Sun Dec 18, 2011 6:25 pm

billdango wrote: After that it gradually gets lighter i think by about 4 minutes per day.
It varies as the sun height and day length is a sine wave so day length and sun height movement are slowest around the summer and winter solstice and fastest around the equinox. :wink:
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Dave
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kata
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Re: THE SHORTEST DAY.

Post by kata » Sun Dec 18, 2011 6:27 pm

Happens every night in our house! Want an invite?!!
Prove it.... :lol: :lol: :lol: :lol: :lol:
http://flowersnpalms.com/floraandfaunauk/

Rain...nowt but rain...Welcome to Lancashire............ :lol: :lol: :lol:


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Springy
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Re: THE SHORTEST DAY.

Post by Springy » Sun Dec 18, 2011 7:31 pm

kata wrote:
Prove it.... :lol: :lol: :lol: :lol: :lol:
I'd love to Kata but it happens in pitch black darkness so you wouldn't be able to see anything!

I bet you would love it though! :lol:


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kata
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Re: THE SHORTEST DAY.

Post by kata » Sun Dec 18, 2011 8:21 pm

Would I Springy,

How do you know that... :lol: :lol: :lol: :lol: :lol: :lol:

We are still talking may polling are we...frillies n all that finished off with pretty ribbons...HAHAHAHAHAHAHA :mrgreen: :mrgreen: :mrgreen: :mrgreen:
http://flowersnpalms.com/floraandfaunauk/

Rain...nowt but rain...Welcome to Lancashire............ :lol: :lol: :lol:


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flounder
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Re: THE SHORTEST DAY.

Post by flounder » Sun Dec 18, 2011 9:37 pm

:shock:
my name is flounder, but you can call me.............flounder! (or Gary, just don't call me late for dinner)


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Darlo Mark
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Re: THE SHORTEST DAY.

Post by Darlo Mark » Mon Dec 19, 2011 1:13 pm

We're nearly at the bottom of the year!
Winter lows:
Winter 2009-10 -9.5
Winter 2010-11 -15.0
winter 2011-12 (so far) -7.2


GREVILLE
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Re: THE SHORTEST DAY.

Post by GREVILLE » Mon Dec 19, 2011 9:52 pm

To all our experts in Astronomy, Meteorology and Pure Mathematics - What's behind the following anomaly around the shortest day? :

In London, the shortest day has a sunrise at 8:02 and a sunset at 15:54 giving a daylight total of 7 hours and 52 minutes. About ten days either side of this, the daylight totals are equally 7 hours and 57 minutes.

The sunrise and sunset times do not separate in equal lengths, however.

On 12th December the London sunrise is 7:55 and the sunset is 15:52 - two minutes earlier than that of the shortest day.
Conversely, on 31st December the sunrise is 8:05 (three minutes later than that of the shortest day) and the sunset is 16:02.

Simply put: Why is the earliest sunset in the year more than a week before the shortest day and why is the latest sunset in the year more than a week past the shortest day?

The shortest (and simplest) answer wins the longest night out (this time next year) :lol:


Conifers
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Re: THE SHORTEST DAY.

Post by Conifers » Mon Dec 19, 2011 10:13 pm

GREVILLE wrote:To all our experts in Astronomy, Meteorology and Pure Mathematics - What's behind the following anomaly around the shortest day? :

In London, the shortest day has a sunrise at 8:02 and a sunset at 15:54 giving a daylight total of 7 hours and 52 minutes. About ten days either side of this, the daylight totals are equally 7 hours and 57 minutes.

The sunrise and sunset times do not separate in equal lengths, however.

On 12th December the London sunrise is 7:55 and the sunset is 15:52 - two minutes earlier than that of the shortest day.
Conversely, on 31st December the sunrise is 8:05 (three minutes later than that of the shortest day) and the sunset is 16:02.

Simply put: Why is the earliest sunset in the year more than a week before the shortest day and why is the latest sunset in the year more than a week past the shortest day?

The shortest (and simplest) answer wins the longest night out (this time next year) :lol:
It's because the Earth's orbit is elliptical, not circular. With an elliptical orbit, the Earth doesn't move round the sun at a constant speed, but is faster at some times (when closer to the sun) than others (slower when more distant from the sun). But regular clock time assumes a circular orbit with equal 24 hour divisions. The result is that the Earth is sometimes slightly 'ahead' of the position it would have on a circular orbit, sometimes slightly 'behind', pushing both sunrise and sunset forward or backward by a few minutes.

Much more detail about it here. Be warned, it's quite complex :lol:


GREVILLE
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Re: THE SHORTEST DAY.

Post by GREVILLE » Wed Dec 21, 2011 6:08 pm

Congrats to Conifers icon_cheers - the only man brave enough to provide a simple answer :lol:

I think my astronomy encyclopedia was quoted by Wiki as the explanations are near enough the same. A student asked me this recently and I had the devils own job trying to give him a simple answer icon_study Hope you don't fine me for copyright :shock:

BTW the prize has gone to the best place in England - the longest night out will be much longer in Northumberland than anywhere down here :lol: - awarded on the shortest day icon_thumright


Conifers
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Re: THE SHORTEST DAY.

Post by Conifers » Wed Dec 21, 2011 6:30 pm

At least for a wonder, it won't be a cold night out! Still just over 10° here icon_cheers


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billdango
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Re: THE SHORTEST DAY.

Post by billdango » Thu Dec 22, 2011 4:47 pm

Todays the day?

Everything gets better from now on and spring is not that far off.

Billdango. icon_cheers icon_cheers icon_cheers icon_cheers


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The Codfather
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Re: THE SHORTEST DAY.

Post by The Codfather » Thu Dec 22, 2011 4:50 pm

Spring is a full season away.....today is the first day of winter ! icon_study
AKA - Martin

Wish list - Big Palms or Dicksonia antarctica's but open to anything really.....Cash Waiting !


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Springy
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Re: THE SHORTEST DAY.

Post by Springy » Thu Dec 22, 2011 4:55 pm

Yeehar!! I'm all dolled up in my frillies and ribbons and dancing my tights off!

Maybe that is too much information!! :oops:

Roll on spring! icon_cheers


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billdango
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Re: THE SHORTEST DAY.

Post by billdango » Thu Dec 22, 2011 4:58 pm

The Codfather wrote:Spring is a full season away.....today is the first day of winter ! icon_study
True? but it still feels good thinking about it?

Anyway; Spring often starts here on the South coast by mid February.

billdango icon_cheers


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The Codfather
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Re: THE SHORTEST DAY.

Post by The Codfather » Thu Dec 22, 2011 5:05 pm

Bill your spring would equal mt summer :lol: :lol:

But yes, 3 mins a day lighter.
AKA - Martin

Wish list - Big Palms or Dicksonia antarctica's but open to anything really.....Cash Waiting !


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